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When, however, sex is born and a male germ-cell unites with a female germ-cell to form a new organism, each cell proceeds, as the first step in the process, to get rid of half of these chromosomes, so that the new organism has precisely the normal number of chromosomes, half of which are derived from the father and the other half from the mother germ-cell.
It may be so, at any rate it does for an illustration. The germ-cell is always microscopic. A little beginning is a prophecy of a great ending.
Of course neither Spencer nor any one else, until the re-discovery of Mendel's work, had any notion at all of the remarkable fashion in which these units are treated in the process whereby germ-cells are prepared for their great destiny. The rule, as we now know, is that one germ-cell contains any given unit, while another does not.
Sir Clifford Allbutt's view, referred to in the following letter, probably had reference to the fact that the sperm-cell goes, or is carried, to the germ-cell, never vice versa. In this letter Darwin gives the reason for the "law" referred to. It is to these articles, as well as to my letters, that Darwin chiefly refers." Down, Bromley, Kent, S.E. April 30, 1868.
They are of diverse shapes and contents, and perform various different operations. The first formation of every animal is accomplished by the agency of cells, and may be illustrated by the egg of any bird or fowl. In the yelk floats the germ-cell, b, which is the point where the formation of the future animal commences.
We may eat ever so many beef-steaks without acquiring any of the characteristics of an ox. And the germ-cell may devour any amount of egg-protoplasma without losing its original paternal energy. As a rule a child inherits as many qualities from its mother as from its father. Sex is determined after conception has taken place. At an early stage of the embryo certain cells are set apart.
He felt that everything in the ancient monastery was dying, save Christ in the tabernacle. As the germ-cell of ecclesiastical organism, the centre from which Christian warmth irradiates upon the world, the monastery was becoming ossified by the action of inexorable age.
Whether the subject of our inquiry be a germ-cell, or a phenomenon so complex as the commencement of a new religion, or the origination of a new disease, or a new phase in civilization, it is alike impossible to do more than to state the conditions under which the fresh growth begins, and to point out what are its manifestations.
The Mendelians are teaching us, too, that their "factors," the units of which we are made, are often intertangled or mutually repellent. If such-and-such goes into the germ-cell, so must something else; or if the one, then never the other.
Whether, as among the lowest forms of life, these two cells are seemingly identical in nature; or whether, as among higher forms, they are distinguishable into sperm-cell and germ-cell; it remains throughout true that from their combination results the mass out of which is evolved a new organism or new series of organisms.
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